This invention relates to a chuck assembly for holding and positioning a workpiece and relates, in particular, to a chuck assembly for holding and positioning a tube with tube fitting mounted thereon.
In order to accurately bend hydraulic tubing into desired shapes, an end of the tube assembly must be securely held and accurately positioned. Tube holding chucks are available to perform this function. One such chuck has an over-center, lever-type linkage which is used to pivot axial tube-engaging jaws to a clamping position while simultaneously, axially moving a tube-locating pilot into engagement with an end of the tube. However, such chucks do not tolerate inconsistencies in tube parts sizes, even when those inconsistencies fall within normal part variation tolerances. For example, slightly undersized tube parts may slip when the chuck is rotated to reposition the tube, whereas oversized tube parts may be deformed by clamping pressure from the jaws. Furthermore, variation in part sizes can lead to undesirable variations in part locations since the over-center linkage may "lock up" with the tube-locating pilot in differing axial positions.